Drug repurposing strategies for COVID-19

COVID-19 has now been declared a pandemic and new treatments are urgently needed as we enter a phase beyond containment. Developing new drugs from scratch is a lengthy process, thus impractical to face the immediate global challenge. Drug repurposing is an emerging strategy where existing medicines, having already been tested safe in humans, are redeployed to combat difficult-to-treat diseases. While using such repurposed drugs individually may ultimately not yield a significant clinical benefit, carefully combined cocktails could be very effective, as was for HIV in the 1990s; the urgent question now being which combination.

Photochemical Rearrangement of a 6-Azasteroid Oxaziridine to a Novel 17β-Carbomethoxy-A-homo-B-seco-6-aza-3, 5-androstanedione

4- and 6-azasteroids have been shown to be potent inhibitors of human 5α-reductase and certain azasteroids have shown significant clinical benefit in the treatment of androgen-related disorders. In an effort to expand the diversity of steroidal heterocycles synthetically accessible for structure-activity relationship exploration, a novel reaction sequence was applied to the preparation of the 6-azasteroid framework. To this end, photolysis of the oxaziridine derived from 17β-carbomethoxy-3β-triisopropylsilyloxy-6-azaandrost-5-ene (1) yielded a novel 7, 5-steroidal ring system that was evaluated for inhibition of human type 1 and 2 5α-reductase.